This invention relates to a test piece for ultrasonic testing having a test defect or test reflector of a certain type, position and size for the testing or calibration of ultrasonic testing apparatus or ultrasonic testing heads.
The invention is intended for use in nondestructive material testing.
For the calibrating of ultrasonic testing apparatus and/or testing heads and for identifying and recognizing a defect test reflectors or small test defects are required. Circular-disk reflectors are known, for example, in the form of pocket bores with a flat bottom. However, bores of this type cannot be made arbitrarily small, especially when the bottom is to be flat.
On the other hand, with the increasing exhaustion of the stability potentials of new materials, such as powder metal superalloys or highly stable ceramics, it is necessary to detect increasingly small defects in the material. As a result, a miniaturization of the ultrasonic testing technology is required.
It is an objective of the invention to provide a test piece having a very small test defect .phi..ltoreq.0.5 mm so that it can be reproduced with respect to position and sound behavior. Also, the test piece must be easily produced and must contain a reflector of any shape that must, however, be able to be reproduced.
This objective is achieved by means of a test base for ultrasonic testing having a test defect or test reflector of a predetermined configuration, position and size for the testing or the calibration of ultrasonic testing apparatus and ultrasonic testing heads comprised of inserts forming the test defect that, with their largest longitudinal dimension are arranged in acoustic irradiation direction and have a reflection surface for the generating of an ultrasonic echo that is no larger than about 0.2 square millimeters and faces the surface of the test piece against which the test head rests during the ultrasonic testing period.
It is another object of the invention to create a test piece wherein the reflection surface of the insert has a fixed distance to the surface serving as the contact surface for the test head.
It is another object of the invention to create a test piece wherein the reflection surface is convex or concave in the direction of the sound.
It is another object of the invention to practice a method of forming a test piece according to a power-metallerical step such as an isostatic cold and/or hot compacting.
It is another object of the invention to produce a test piece comprised of pulverizable metal, intermemtallic phases or ceramics.
It is another object of the invention to produce a test piece containing an insert or inserts compacted in a rod shaped, needle shape or fiber shape.
It is another object of the invention to produce a test piece comprising inserts of quartz glass, diamond or sapphire.
It is another object of the invention to produce a test piece having inserts which have a reflection surface arranged symmetrically around an axis and in certain embodiments are conical.
It is another object of the invention to produce a test piece wherein reflection surfaces are of assymetrical symmetrical shape.
It is another object of the invention to produce a test piece wherein the reflection surface is composed of slanted or partial surfaces.
The invention makes it possible to produce a test piece having replacement defects and/or replacement reflectors (inserts) of a magnitude of about 0.01 to 0.05 mm that can be reproduced and are defined geometrically within narrow limits. The invention also makes it possible to produce reflectors in almost arbitrarily reproduceable shapes and to determine related influences on the ultrasonic signal. The test piece, in this case, consists of pulverizable metal, intermetallic phases or ceramics. The inserts advantageously consist of quartz glass or a material with a similar behavior.
The foregoing and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for the purposes of illustration only, plural embodiments in accordance with the present invention, and wherein: